Mr Niinisto, a former finance minister, was given 37% of the vote in a prediction by national broadcaster YLE. Official results with 80% of votes counted also showed him with a clear lead.

This suggested he would face either Paavo Vayrynen, a former foreign minister, or Greens candidate Pekka Haavisto in a second round next month.

Mr Haavisto, the first openly gay presidential candidate in Finland, got 18% in YLE's forecast, just ahead of Mr Vayrynen with 17.8%.

Populist leader Timo Soini, the face of euroskepticism in Finland, was a distant fourth with 9.6%.

The vote comes as the Nordic country braces for cutbacks amid a European financial crisis that threatens the economy and the top credit rating of the eurozone member.

The president has a largely ceremonial role and is not involved in daily politics, but is considered an important figure in the shaping of public opinion.

Mr Niinisto, 63, of the conservative National Coalition Party, was narrowly defeated in the previous election in 2006 by outgoing president Tarja Halonen. This time, he had topped the polls for months in the field of eight candidates.

Political analyst Olavi Borg said: "It's 99% sure that Niinisto will win the presidency, if not in the first round then in a run-off. A miracle would have to happen for him not to win."